1. Field of the Invention
The invention relates to a window blind, more particularly to a window blind having a retrainable bottom rail.
2. Description of the Related Art
A conventional window blind includes a hollow horizontal headrail, a plurality of slats disposed under and parallel to the headrail, a bottom rail disposed under and parallel to the slat unit, and a pair of pull ropes. Each of the pull ropes has a vertical section that passes through a hole formed in a respective end portion of each of the slats, a mounting end that is fastened to the bottom rail, and an actuator end that extends out of the headrail. The actuator end is suspended from the headrail and is operable to raise and lower the slats. Although the conventional window blind achieves the purpose of blocking light and vision into a room when the slats are lowered, there are certain drawbacks associated with the conventional window blind. For instance, since the bottom rail is not retrained, strong gusts of wind may cause the bottom rail to sway back and forth, which creates undesirable noise when the bottom rail hits a wall. Another drawback is that the actuator ends of the pull ropes lengthen when the slat are raised and are easily reached by children, which is dangerous in view of possible entanglement.
Therefore; the object of the present invention is to provide a window blind that has a retrainable bottom rail so as to overcome the aforesaid drawbacks of the prior art.
According to the present invention, a window blind comprises a hollow horizontal headrail, a slat unit, a hollow bottom rail, and a pair of pull ropes. The slat unit includes a plurality of parallel slats disposed under and parallel to the headrail. Each of the slats has two spaced apart holes. The hollow bottom rail is disposed under and parallel to the slats. Each of the pull ropes has a vertical section which passes through one of the holes in each of the slats, a turning section which extends below the vertical section within the bottom rail and which is inclined from the vertical section, a mounting section which extends inclinedly from the turning section, which extends out from the bottom rail and which is adapted to be fixed to a wall below the bottom rail, and a pulling section which extends above the vertical section and which is suspended from the headrail. The pulling section is operable so as to set a tension level on the vertical, turning and mounting sections. The bottom rail has two spaced apart entrance holes adjacent to the slat unit, and two spaced apart exit holes provided below the entrance holes. The vertical section ends at one of the entrance holes. The turning section extends from one of the entrance holes to one of the exit holes and provides a frictional retention force to retain the bottom rail at a desired height.